WO2022107321A1

WO2022107321A1 - Display panel, display device, and method for manufacturing display panel

Info

Publication number: WO2022107321A1
Application number: PCT/JP2020/043442
Authority: WO
Inventors: 勇三中野
Original assignee: 三菱電機株式会社
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2022-05-27

Abstract

The purpose of the present disclosure is to protect, in a display device configured by arranging a plurality of display panels in a matrix, protect side surfaces of light emitting elements located at the outermost periphery of each of the display panels. A display panel (11) according to the present disclosure comprises: a substrate (3); a plurality of LED elements (2) disposed apart from each other on the upper surface of the substrate (3), and each having a light emission surface on the side opposite to the substrate (3); a black fiber mesh (5) inserted between the plurality of LED elements (2); and a transparent adhesive (4) that abuts on the upper surface of the black fiber mesh (5), is formed on the light emission surface sides of the plurality of LED elements (2), and has light transmittivity.

Description

Display panel, display device and manufacturing method of display panel

This disclosure relates to the display panel.

There is known an LED display device in which a plurality of LED (Light Emitting Diode) elements are arranged in a square array and video information is displayed by controlling blinking of each LED element.

LED display devices are widely used for outdoor and indoor advertisement display due to technological development and cost reduction of LED elements. In recent years, LED display devices have become shorter in viewing distance as the pixel pitch becomes narrower, so that they are also used for displaying images on personal computers, and are used in conference rooms and surveillance applications. In particular, in surveillance applications, LED display devices often display personal computer images close to still images.

Currently, the mainstream of LED display devices is the SMD (Surface Mount Device: surface mount component) type. The SMD type is a type in which an LED element is mounted in a cavity molded of ceramic or resin, and a small LED package hardened with a sealing resin is mounted on a substrate.

LED display devices have been widely used as large display devices with a pixel pitch of 3 mm or more. However, in recent years, due to the demand for lower cost and higher definition LED elements, SMD type LED display devices with pixel pitches of 2.5 mm, 1.9 mm, 1.5 mm, and 1.2 mm have been introduced to the market. It has been put in.

Further, instead of individually cavityd SMD type LED elements, 4in1 type SMD type LED elements in which LED elements constituting 4 pixels are sealed in one package, or LED elements without an outer shell are directly mounted on the substrate. There is an LED display device that achieves higher definition and higher density by adopting a COB (Chip On Board) type LED element. Such LED display devices have a pixel pitch of less than 1 mm and are so-called mini LEDs or micro LEDs.

For example, in the dot matrix light emitting display body described in Patent Document 1, a mask plate having a light reflecting surface and a mortar-shaped through hole formed around each of a large number of LED elements arranged vertically and horizontally is arranged inside the through hole. The translucent resin is sealed in. Further, in front of the LED element and the mortar-shaped hole, a surface condensing plate in which a convex lens made of a translucent resin is fitted in a through hole through a gap is arranged. As a result, in the dot matrix light emitting display, the desired orientation characteristics are obtained, the light utilization efficiency is increased, and the contrast is improved.

Jitsukaihei No. 5-52882

A large LED display device is configured by arranging a plurality of LED display panels in the vertical direction and the horizontal direction. At this time, in the LED display panel with high definition and high density, there are problems such as the side surfaces of the LED elements (light emitting elements) arranged on the outermost periphery of the adjacent LED display panel colliding with each other and being damaged. Is likely to occur.

Therefore, an object of the present disclosure is to protect the side surface of the light emitting element located on the outermost periphery of each display panel in a display device in which a plurality of display panels are arranged in a matrix.

The display panel of the present disclosure is made of a substrate, a plurality of light emitting elements arranged apart from each other on the upper surface of the substrate, and having a light emitting surface on the opposite side of the substrate, and a fiber inserted between the plurality of light emitting elements. It comprises a black matrix layer and a pressure-sensitive adhesive that is in contact with the upper surface of the black matrix layer and is formed on the light emitting surface side of a plurality of light emitting elements and has translucency.

According to the technique of the present disclosure, in a display device in which a plurality of display panels are arranged in a matrix, it is possible to protect the side surface of a light emitting element located on the outermost periphery of each display panel. The purposes, features, embodiments, and advantages of the present disclosure will be made clearer by the following detailed description and accompanying drawings.

It is a top view of the display device of Embodiment 1. FIG. It is sectional drawing of the display panel of Embodiment 1. FIG. It is a top view of the display panel of Embodiment 1. FIG. It is sectional drawing of the display panel of Embodiment 1. FIG. It is a top view of the black fiber mesh which constitutes the display panel of Embodiment 1. FIG. It is sectional drawing of the black fiber mesh which constitutes the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 1. FIG. It is a top view which shows the state which attached the ground wire to the display device of Embodiment 1. FIG. It is sectional drawing of a plurality of display panels constituting the display device of Embodiment 1. FIG. It is sectional drawing which shows how the black fiber mesh is peeled off from the LED element in the display panel of Embodiment 1. FIG. It is a top view which shows the state before excision of the protruding part of the display panel of Embodiment 2. FIG. It is sectional drawing which shows the state before excision of the protruding part of the display panel of Embodiment 2. It is a top view which shows the state before excision of the protruding part of the black fiber mesh which constitutes the display panel of Embodiment 2. FIG. It is sectional drawing which shows the state before excision of the protruding part of the black fiber mesh which constitutes the display panel of Embodiment 2. FIG. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 2. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 2. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 2. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 2. It is sectional drawing which shows the manufacturing process of the display panel of Embodiment 2. It is a top view which shows the state which the protruding part of the display panel of Embodiment 2 is cut off. It is sectional drawing which shows the state that the protruding part of the display panel of Embodiment 2 is cut off. It is a top view which shows the state after excision of the protruding part of the display panel of Embodiment 2. FIG. It is sectional drawing which shows the state after excising the protruding part of the display panel of Embodiment 2. It is a top view which shows the state after excising the protruding part of the black fiber mesh of Embodiment 2. FIG. It is sectional drawing which shows the state after excising the protruding part of the black fiber mesh of Embodiment 2.

<A. Embodiment 1>
<A-1. Configuration>
FIG. 1 is a front view of the display device 101 of the first embodiment. The display device 101 is configured to include a plurality of display panels 11. The plurality of display panels 11 are arranged in a matrix in the vertical direction and the horizontal direction to form one large screen. In the example of FIG. 1, nine display panels 11 are arranged vertically and horizontally to form a display device 101.

FIG. 2 is a cross-sectional view of the display panel 11 along the line AA of FIG. FIG. 3 is a plan view of the display panel 11 shown in the area B of FIG. FIG. 4 is a cross-sectional view of the display panel 11 in which the area C of FIG. 2 is enlarged.

As shown in FIG. 2, the display panel 11 includes a substrate 3, a plurality of LED elements 2, a transparent substrate 1, a transparent adhesive 4, and a black fiber mesh 5. Each LED element 2 is a light emitting element. The transparent substrate 1 is a protective base material. The black fiber mesh 5 is a black matrix layer. In FIG. 2, 64 LED elements 2 are arranged in a matrix of 8 in the vertical direction and 8 in the horizontal direction. However, the number of LED elements 2 constituting the display panel 11 is not limited to this. In addition, in FIGS. 1 and 3, the transparent substrate 1 and the transparent adhesive 4 are not shown for the purpose of making the figure easier to see.

The substrate 3 is an epoxy substrate containing glass fiber.

The plurality of LED elements 2 are SMD type LED elements, and are bonded to electrodes (not shown) exposed on the surface of the substrate 3 by solder or the like. The plurality of LED elements 2 are mounted on the upper surface of the substrate 3 so as to be separated from each other, and have a light emitting surface on the upper surface which is a surface opposite to the substrate 3 side.

As shown in FIG. 4, each LED element 2 includes a red LED element 2r, a green LED element 2g, a blue LED element 2b, and an epoxy-based encapsulating resin 6 for encapsulating them. Each LED element 2 is molded as a rectangular chip component by the epoxy-based sealing resin 6. The epoxy-based sealing resin 6 has translucency. The epoxy-based sealing resin 6 covers the light emitting surface of the red LED element 2r, the green LED element 2g, and the blue LED element 2b.

Although not shown in FIGS. 2 and 4, the side surface and the upper surface of each LED element 2 may be coated with a light release agent, a resin adhesion inhibitor, or an ultraviolet light-shielding coating. The light release agent is fluorine-based or silicone-based. The ultraviolet light-shielding coating is, for example, a coating in which an ultraviolet scattering agent typified by titanium oxide or an ultraviolet absorbing agent is dispersed in an acrylic resin or the like.

The transparent substrate 1 has translucency. The transparent substrate 1 faces the light emitting surface of each LED element 2 via the transparent adhesive 4. The transparent substrate 1 may be optically transparent. The transparent substrate 1 may be a polycarbonate, acrylic, polyester, cycloolefin polymer, or a thin film transparent resin film having a film thickness of 0.1 mm or more and 3 mm or less, which is obtained by laminating a plurality of these. Polyesters include polyethylene terephthalate, polyethylene naphthalate, liquid crystal polymers and the like. In the first embodiment, the transparent substrate 1 will be described as a thin film transparent resin film.

The upper surface of the transparent substrate 1 opposite to the LED element 2 may be subjected to AR (Anti Reflection) treatment or AG (Anti Glare) treatment in order to prevent external light reflection.

The transparent adhesive 4 is arranged between the plurality of LED elements 2 and the transparent substrate 1. The transparent pressure-sensitive adhesive 4 is, for example, a heat-curable type, UV-curable type, moisture-curable type, or UV moisture-curable acrylic pressure-sensitive adhesive, silicone-based pressure-sensitive adhesive, or urethane-based pressure-sensitive adhesive having translucency.

As shown in FIG. 3, the black fiber mesh 5 is composed of a plurality of warp threads 5a and weft threads 5b, and has a black matrix function having an external light absorption effect. The black fiber mesh 5 is arranged in a gap between adjacent LED elements 2 surrounded by a substrate 3 and a transparent adhesive 4. Further, the black fiber mesh 5 is also arranged on the outer peripheral side surface of the LED element 2 arranged on the outermost peripheral portion of the display panel 11 and in a space surrounded by the substrate 3 and the transparent adhesive 4.

The upper surface of the black fiber mesh 5 is located at substantially the same height as the light emitting surface of each LED element 2, and is adhered to the lower surface of the transparent adhesive 4. A gap 9 is formed between the black fiber mesh 5 and the substrate 3. That is, the lower surface of the black fiber mesh 5 is not in contact with the upper surface of the substrate 3.

FIG. 5 is a front view showing an example of the black fiber mesh 5. FIG. 6 is a cross-sectional view of the black fiber mesh 5 along the DD line of FIG. The material of the black fiber mesh 5 is, for example, carbon fiber, kepler fiber, glass fiber, acrylic fiber, polyester fiber, glass fiber coated with polyvinyl chloride, or a combination of various fiber materials thereof. In the first embodiment, the black fiber mesh 5 is described as being formed by knitting a plurality of warp threads 5a and weft threads 5b made of carbon fibers.

<A-2. Manufacturing method>
Next, a method of manufacturing the display panel 11 will be described with reference to FIGS. 7 to 15. 7 to 15 are cross-sectional views for explaining each step in the manufacturing method of the display panel 11. Hereinafter, a case where an insulating coating and a light release agent coating are applied to the upper surface and the side surface of each LED element 2 will be described.

First, as shown in FIG. 7, the LED display board 8 is prepared and set on the jig 7. The LED display board 8 is composed of a board 3 and a plurality of LED elements 2 mounted in a matrix on the upper surface of the board 3 apart from each other. Here, the size of the LED element 2 is 1.0 mm in both vertical and horizontal directions, and the height is 0.6 mm. The pixel pitch is 1.5 mm. That is, the gap between the adjacent LED elements 2 has a width of 0.5 mm.

After that, as shown in FIG. 8, the surface of the substrate 3 on which the LED element 2 is mounted is subjected to an insulating coating treatment so as to cover the upper surface of the substrate 3 and the solder portion of the LED element 2. As a result, the insulating coating layer 20 is formed in the gap between the adjacent LED elements 2 on the upper surface of the substrate 3.

Next, as shown in FIG. 9, a light peel coating layer 22 is formed on the side surface and the upper surface of the LED element 2 on the insulating coating layer 20.

After that, as shown in FIG. 10, a mesh-like black fiber mesh 5 is fitted in the gaps between the plurality of LED elements 2. The black fiber mesh 5 has a structure in which carbon fibers having a diameter of 0.5 mm are woven vertically and horizontally.

Next, as shown in FIG. 11, a gel-like transparent adhesive 4 is thinly applied to the upper surfaces of the light release coating layer 22 and the black fiber mesh 5. Here, the transparent pressure-sensitive adhesive 4 is a thermosetting type. A slit coater, a bar coater, a dispenser, or the like can be used for applying the gel-like transparent adhesive 4, but the present invention is not limited to this. The coating film thickness of the gel-like transparent adhesive 4 depends on the size and pixel pitch of the LED element 2. The dimensions of the LED element 2 are vertical W x horizontal D mm, the height from the substrate 3 after mounting the LED element 2 is H mm, the pixel pitch is P mm, and the final thickness of the transparent adhesive 4 after curing is T'mm. Assuming that the curing shrinkage rate of the transparent adhesive 4 is S%, the volume of the black fiber mesh 5 is V, and the average thickness of the black fiber mesh 5 is A, the coating film thickness T of the gel-like transparent adhesive 4 is as follows. It is obtained by the formula (1). However, T'<H <A. Here, the final thickness of the transparent pressure-sensitive adhesive 4 after curing is set to 0.25 mm or more and 0.5 mm or less.

After that, as shown in FIG. 12, the transparent substrate 1 is put on the gel-like transparent adhesive 4. The transparent substrate 1 is made of polyethylene terephthalate (PET) and has a thickness of 0.1 mm or more and 0.3 mm or less. Then, the black fiber mesh 5 is pulled up to the height of the upper surface of the LED element 2 on the transparent substrate 1 side to secure a gap 9 between the substrate 3 and the black fiber mesh 5. The void 9 and the insulating coating layer 20 covering the upper surface of the substrate 3 and the solder portion of the LED element 2 formed in the process shown in FIG. 9 provide an insulating property between the LED element 2 and the black fiber mesh 5. It is secured.

Next, as shown in FIG. 13, a pressing roller 23, a vacuum pump, or the like is used to expel air bubbles that have been caught in the gel-like transparent adhesive 4. In FIG. 13, the exhaust hole connected to the vacuum pump is indicated by reference numeral 24. Then, the transparent adhesive 4 is cured by heat and pressure treatment by an autoclave device. When the transparent adhesive 4 is cured, the LED display substrate 8, the black fiber mesh 5, and the transparent substrate 1 are integrated via the transparent adhesive 4. In this way, the display panel 11 including the LED display substrate 8, the insulating coating layer 20, the light peeling coating layer 22, the black fiber mesh 5, the transparent adhesive 4, and the transparent substrate 1 is obtained.

Next, as shown in FIG. 14, the display panel 11 is removed from the jig 7.

Finally, as shown in FIG. 15, a portion of the display panel 11 that protrudes from the outer periphery of the substrate 3 (hereinafter referred to as “protruding portion 14”) is cut off, and the display panel 11 is molded into a product size.

The jig 7 is used as a holding jig for forming the insulating coating layer 20 and the light peeling coating 22 layer on the LED display board 8, and the LED display board 8, the black fiber mesh 5, and the transparent board 1 are transparently adhered to each other. It is used as an adhesive jig for integrating with the agent 4. In the first embodiment, since heat is used to cure the transparent pressure-sensitive adhesive 4, the jig 7 is preferably a non-metal material having a small heat capacity.

By the above manufacturing process, the display panel 11 of the first embodiment can be obtained. After that, one display device 101 is obtained by arranging a plurality of display panels 11.

FIG. 16 is a front view showing a state in which the ground wire 25 is attached to the display device 101. FIG. 17 is a cross-sectional view of a region F of the display device 101 along the line EE of FIG. As shown in FIG. 1, in the display device 101, the black fiber mesh 5 on the outermost circumference of one display panel 11 is black on the outermost circumference of another display panel 11 adjacent to the display panel 11 due to its elastic force. It adheres to the fiber mesh 5. Therefore, the black fiber mesh 5s in the display panels 11 constituting the display device 101 are in electrical contact with each other.

Although not shown in FIGS. 16 and 17, the display device 101 has an aluminum die-cast holding housing on the substrate 3 side of each display panel 11 in order to fix the plurality of display panels 11 in a state of being arranged in a matrix. I have. At the outermost peripheral portion of any display panel 11 arranged on the outermost circumference of the display device 101, the ground wire 25 is arranged so as to be in contact with the holding housing and the warp and weft 5a and the weft 5b of the black fiber mesh 5. Not only the two display panels 11, but also the entire surface of the display device 101, an unnecessary radiation shielding effect can be obtained, and static electricity is less likely to accumulate, and an antistatic effect can be obtained.

<A-3. How to replace the pixel unit>
FIG. 18 is a diagram showing an outline of a method of replacing the LED element 2 in the display panel 11. In the display panel 11, the transparent substrate 1 is made of a film-like polyethylene terephthalate (PET) having a thickness of 0.1 mm or more and 0.3 mm or less, and a light peeling coating layer 22 is formed on the surface and side surfaces of the LED element 2. ing. Therefore, the transparent substrate 1 and the black fiber mesh 5 integrated with the transparent adhesive 4 can be integrally turned over from the end portion and peeled from the LED element 2 with the help of the light peeling coating layer 22. Is.

Further, since the gap 9 is secured between the black fiber mesh 5 and the substrate 3 by adjusting the diameter and the number of the warp 5a and the weft 5b of the black fiber mesh 5, they are integrated by the transparent adhesive 4. The transparent substrate 1 and the black fiber mesh 5 can be more easily peeled off from the LED element 2.

As described above, when the LED element 2 needs to be replaced and repaired, the transparent substrate 1 and the black fiber mesh 5 integrated with the transparent adhesive 4 are easily peeled off from the LED element 2 to be easily peeled off from the LED element 2. Can be exposed. Therefore, the LED element 2 that needs to be replaced and repaired can be easily replaced.

<A-4. Modification example>
A light peel coating may be applied to the surface of the transparent substrate 1 with respect to the transparent adhesive 4. In this case, the transparent substrate 1 is covered with the transparent adhesive 4, the transparent adhesive 4 is heat-cured, the transparent substrate 1 is temporarily fixed to the LED element 2 and the black fiber mesh 5, and then the transparent substrate 1 is transparently adhered. The display panel 11 is formed by peeling from the agent 4. That is, in this modification, the display panel 11 does not have the transparent substrate 1. Therefore, the decrease in the brightness of the display light due to the transparent substrate 1 is suppressed.

<A-5. Effect>
The display panel 11 of the first embodiment includes a substrate 3, a plurality of LED elements 2 which are light emitting elements, a black fiber mesh 5 which is a black matrix layer made of fiber, and a transparent adhesive 4. The plurality of LED elements 2 are arranged on the upper surface of the substrate 3 so as to be separated from each other, and have a light emitting surface on the opposite side to the substrate 3. Since the black fiber mesh 5 is fitted between the plurality of LED elements 2, even if the pixel pitch of the LED element 2 is narrow, the black fiber mesh 5 can be selected by selecting the fiber diameter and mesh pitch of the black fiber mesh 5. Can be arranged between the LED elements 2.

Further, in the display panel 11 of the first embodiment, the transparent adhesive 4 is in contact with the upper surface of the black fiber mesh 5 and is formed on the light emitting surface side of the plurality of LED elements 2 to have translucency. Therefore, the upper surface of the black fiber-mesh 5 and the light emitting surface of each LED element 2 are close to the same surface, and the black fiber mesh 5 and the LED adjacent thereto are close to each other regardless of the height of the LED element 2 from the substrate 3. The relative position of the element 2 with respect to the light emitting surface can be kept uniform. Therefore, the effect of absorbing external light by the black fiber mesh 5 is maximized, and the contrast of external light is improved and the visibility is improved.

Further, in the display panel 11 of the first embodiment, the black fiber mesh 5 is arranged in contact with the outer peripheral side side surface of the outermost peripheral LED element 2. Therefore, in the display device 101 configured by arranging a plurality of display panels 11 in a matrix, the side surfaces of the LED elements 2 arranged on the outermost periphery of the adjacent display panels 11 are protected by the black fiber mesh 5. Problems such as damage to the LED element 2 are suppressed.

Further, the display panel 11 of the first embodiment may include a transparent substrate 1 as a protective base material having translucency on the transparent adhesive 4. When the display panel 11 includes the transparent substrate 1, the transparent substrate 1 functions as a protective substrate for the LED element 2.

However, the display panel 11 of the first embodiment does not have to include the transparent substrate 1. In this case, the decrease in the brightness of the display light due to the transparent substrate 1 can be avoided.

In the display panel 11 of the first embodiment, the black fiber mesh 5 may be arranged with a gap 9 between the display panel 11 and the upper surface of the substrate 3. This makes it possible to easily peel the black fiber mesh 5 from the LED element 2 together with the transparent adhesive 4 and the transparent substrate 1.

In the display panel 11 of the first embodiment, the light peeling coating layer 22 is provided on the side surface and the light emitting surface of each LED element 2, and the black fiber mesh 5 is formed on the side surface of the plurality of LED elements 2 via the light peeling coating layer 22. You may be in contact with. This makes it possible to more easily peel the black fiber mesh 5 from the LED element 2 together with the transparent adhesive 4 and the transparent substrate 1.

In the display panel 11 of the first embodiment, by making the black fiber mesh 5 made of fiber, a fine black fiber mesh 5 having a hardness that can be fitted in a minute gap between the LED elements 2 can be easily formed. Is possible.

The black fiber mesh 5 arranged on each display panel 11 is stretched over the entire surface of the display device 101 by arranging the display panels 11 in a matrix. Therefore, if the black fiber mesh 5 is made of conductive carbon fiber, by connecting the ground wire to the black fiber mesh 5, an unnecessary radiation shielding effect can be obtained, and static electricity is less likely to accumulate and an antistatic effect can be obtained. Be done.

The display device 101 of the first embodiment includes a plurality of display panels 11 of the first embodiment, and the plurality of display panels 11 are arranged to form one screen. Therefore, according to the display device 101, since the side surfaces of the LED elements 2 arranged on the outermost periphery of the adjacent display panels 11 are protected by the black fiber mesh 5, problems such as damage to the LED elements 2 are suppressed.

In the method of manufacturing the display panel 11 of the first embodiment, (a) a substrate 3 in which a plurality of LED elements 2 are mounted on the same surface so as to be separated from each other is prepared, and (b) a black matrix layer is provided in the gap between the LED elements 2. The black fiber mesh 5 is fitted, (c) the transparent adhesive 4 is applied on the black fiber mesh 5 and the LED element 2, (d) the transparent substrate 1 is covered on the transparent adhesive 4, and (e). By pulling up the black fiber mesh 5 and pressing it against the transparent adhesive 4, a gap 9 is formed between the black fiber mesh 5 and the substrate 3, and the transparent adhesive 4 is cured after the step (f) (e). ..

According to the above manufacturing method, by pulling the black fiber mesh 5 toward the transparent substrate 1, the black fiber mesh 5 is pressed against the transparent adhesive 4 and fixed. Therefore, the upper surface of the black fiber mesh 5 and the light emitting surface of the LED element 2 are close to the same surface, and the black fiber mesh 5 and the LED element 2 adjacent thereto are close to each other regardless of the height of the LED element 2 from the substrate 3. The relative position of the light emitting surface can be kept uniform. Therefore, the effect of absorbing external light by the black fiber mesh 5 is maximized, and the contrast of external light is improved and the visibility is improved.

<B. Embodiment 2>
<B-1. Configuration>
The front view of the display device 102 of the second embodiment is as shown in FIG. The display device 102 includes a plurality of display panels 12. The plurality of display panels 12 are arranged in a matrix in the vertical direction and the horizontal direction to form one large screen.

19 and 20 are a front view and a cross-sectional view of the display panel 12 in a state before cutting off the protruding portion 14 from the outer peripheral portion of the substrate 3. FIG. 20 is a cross-sectional view taken along the line GG of FIG. Compared with the display panel 11 of the first embodiment, the display panel 12 has a transparent substrate 31, a transparent adhesive 34, and a black fiber mesh 35 instead of the transparent substrate 1, the transparent adhesive 4, and the black fiber mesh 5. It is the same as the display panel 11 in other respects.

21 and 22 are a front view and a cross-sectional view of the black fiber mesh 35 before excision of the protruding portion 14. FIG. 22 is a cross-sectional view taken along the line HH of FIG. 21.

The transparent substrate 31, the transparent adhesive 34, and the black fiber mesh 35 are made of the same resin. For example, the transparent substrate 31, the transparent adhesive 34, and the black fiber mesh 35 are all made of an acrylic resin. The black fiber mesh 35 is made of acrylic fiber in which carbon black is kneaded as a black colorant. The transparent pressure-sensitive adhesive 34 is a UV-curable acrylic resin. The thickness of the transparent pressure-sensitive adhesive 34 is, for example, 0.25 mm or more and 0.5 mm or less, similar to the transparent pressure-sensitive adhesive 4. The transparent substrate 31 is an acrylic resin. The thickness of the transparent substrate 31 is, for example, 0.1 mm or more and 1.0 mm or less.

The black fiber mesh 35 is composed of a plurality of warp threads 35a and a plurality of weft threads 35b knitted in a single layer. Here, each warp and weft 35a includes two fibers 35a1 and 35a2 arranged side by side, and each warp and weft 35b includes two fibers 35b1 and 35b2 arranged side by side. The diameter of the fibers 35a1, 35a2, 35b1, 35b2 is half the length of the gap between the two adjacent LED elements 2. For example, as in the first embodiment, the size of the LED element 2 is 1.0 mm in both vertical and horizontal directions, the height is 0.6 mm, and the pixel pitch is 1.5 mm. In this case, the gap between the adjacent LED elements 2 has a width of 0.5 mm. The diameter of the fibers 35a1, 35a2, 35b1, 35b2 is 0.25 mm.

<B-2. Manufacturing method>
Next, a method of manufacturing the display panel 12 will be described with reference to FIGS. 23 to 27. 23 to 27 are cross-sectional views for explaining each step in the manufacturing method of the display panel 12. Hereinafter, a case where an insulating coating and a light release agent coating are applied to the upper surface and the side surface of each LED element 2 will be described as in the first embodiment.

The process up to the formation step of the insulating coating layer 20 is the same as the manufacturing method of the display panel 11 of the first embodiment. After forming the insulating coating layer 20, the ultraviolet light-shielding coating layer 21 is formed on the side surface and the upper surface of the LED element 2 on the insulating coating layer 20. After that, the light peeling coating layer 22 is formed on the ultraviolet light-shielding coating layer 21. As a result, the configuration shown in FIG. 23 is obtained.

After that, as shown in FIG. 24, the mesh-like black fiber mesh 35 is fitted into the gaps between the plurality of LED elements 2. This step is the same as the step shown in FIG. 10 of the first embodiment except that the material of the black fiber mesh 35 is different from that of the black fiber mesh 5.

As shown in FIG. 25, a gel-like transparent adhesive 34 is thinly applied to the upper surfaces of the light peeling coating layer 22 and the black fiber mesh 5. This step is the same as the step shown in FIG. 11 of the first embodiment except that the transparent pressure-sensitive adhesive 34 is made of a different material from the transparent pressure-sensitive adhesive 4.

Next, as shown in FIG. 26, the transparent substrate 31 is put on the gel-like transparent adhesive 34. Then, the black fiber mesh 35 is pulled up to the height of the upper surface of the LED element 2 on the transparent substrate 1 side to secure a gap 9 between the substrate 3 and the black fiber mesh 35. This step is the same as the step shown in FIG. 12 of the first embodiment except that the material of the transparent substrate 31 is different from that of the transparent substrate 1.

Next, as shown in FIG. 27, a pressing roller 23, a vacuum pump, or the like is used to expel air bubbles that have been caught in the gel-like transparent adhesive 4. In FIG. 27, the exhaust hole connected to the vacuum pump is indicated by reference numeral 24. Then, the transparent adhesive 34 is cured by the UV irradiation treatment. When the transparent adhesive 34 is cured, the LED display substrate 8, the black fiber mesh 35, and the transparent substrate 31 are integrated via the transparent adhesive 34. In this way, the display panel 12 including the LED display substrate 8, the insulating coating layer 20, the ultraviolet light-shielding coating layer 21, the light peeling coating layer 22, the black fiber mesh 35, the transparent adhesive 34, and the transparent substrate 31 is obtained.

After that, the display panel 12 is removed from the jig 7. This step is the same as the step shown in FIG. 14 in the first embodiment.

Next, the protruding portion 14 of the display panel 12 that protrudes from the outer periphery of the substrate 3 is cut off, and the display panel 12 is molded to the product size. This step is the same as the step shown in FIG. 15 in the first embodiment.

28 and 29 are a front view and a cross-sectional view of the display panel 12 showing how the protruding portion 14 is cut off. FIG. 29 is a cross-sectional view taken along the line I-I of FIG. 28. 30 and 31 are a front view and a cross-sectional view of the display panel 12 after the protruding portion 14 is cut off. FIG. 30 is a cross-sectional view taken along the line JJ of FIG. 32 and 33 are front views and cross-sectional views of the black fiber mesh 35 after the protruding portion 14 has been cut off. 33 is a cross-sectional view taken along the line KK of FIG. 32.

<B-3. Effect>
The display panel 12 of the second embodiment has the following effects in addition to the effect of the display panel 11 of the first embodiment.

The black fiber mesh 35 of the second embodiment is configured by singing a warp and weft 35a formed by arranging fibers 35a1 and 35a2 and a weft 35b formed by arranging fibers 35b1 and 35b2 in a single layer. Therefore, when the protruding portion 14 of the display panel 12 is cut off, the black fiber mesh 35 can be easily cut with the width of one fiber 35a1, 35a2, 35b1, 35b2. That is, it is easy to mold the display panel 12 into a product size.

Further, the fibers 35a1, 35a2, 35b1, 35b2 constituting the black fiber mesh 35 of the second embodiment have a diameter half that of the black fiber mesh 5 of the first embodiment. Therefore, the gap 9 between the black fiber mesh 35 and the substrate 3 is secured to be larger by the diameter of one fiber 35a1, 35a2, 35b1, 35b2 as compared with the first embodiment. As a result, the possibility of electrical contact between the substrate 3 and the black fiber mesh 35 is reduced, and the black fiber mesh 35 can be easily peeled off from the substrate 3.

The black fiber mesh 35 of the second embodiment is made of a resin fiber kneaded with carbon black. In this case, since carbon black has conductivity, by connecting the ground wire to the black fiber mesh 35, an unnecessary radiation shielding effect can be obtained, and static electricity is less likely to accumulate and an antistatic effect can be obtained.

Further, it is desirable that the resin constituting the black fiber mesh 35 of the second embodiment is a resin of the same system as the transparent adhesive 34. As a result, interfacial reflection at the interface between the transparent adhesive 34 and the black fiber mesh 35 is suppressed. As a result, the effect of absorbing external light by the black fiber mesh 35 is enhanced, and the contrast of external light is improved and the visibility is improved. Further, since the bonding force between the transparent adhesive 34 and the black fiber mesh 35 is enhanced, these can be easily and integrally peeled from the substrate 3.

Further, when the black fiber mesh 35 of the second embodiment includes the transparent substrate 31 which is a protective base material, the resin constituting the black fiber mesh 35 is a resin of the same system as the transparent substrate 31 and the transparent adhesive 34. Is desirable. As a result, interfacial reflection at the interface between the transparent substrate 31 and the transparent pressure-sensitive adhesive 34 and the interface between the transparent pressure-sensitive adhesive 34 and the black fiber mesh 35 is suppressed. As a result, the effect of absorbing external light by the black fiber mesh 35 is enhanced, and the contrast of external light is improved and the visibility is improved. Further, since the binding force of the transparent substrate 31, the transparent adhesive 34, and the black fiber mesh 35 is increased, these can be easily and integrally peeled from the substrate 3.

For example, a black colorant may be added to at least one of the transparent substrate 31 and the transparent adhesive 34 so that the transmittance is about 70%. The image light passes through the transparent adhesive 34 and the transparent substrate 31 only once, whereas the external light passes through the transparent substrate 31 and the transparent adhesive 34, and then the transparent adhesive 34 and the LED element 2 or the black fiber mesh 35. The surface is reflected at the interface with the transparent adhesive 34 and the transparent substrate 31 is transmitted again. Therefore, the external light taken out to the outside of the display panel 12 is reduced to the square of the transmittance of the transparent substrate 31 and the transparent adhesive 34 or less. As a result, the external light contrast is improved as compared with the display panel 11 of the first embodiment.

The approximate value of the external light contrast improvement rate CI is calculated by the following equations (2)-(4). However, the brightness of the video light of the default white signal output from each LED element 2 of the display panel 12 is W, the brightness of the video light of the default black signal is B, and the brightness of the external light incident on the display panel 12 is A. And. Further, C1 is the external light contrast when there is no LED surface protection structure, and C2 is the external light contrast when there is no LED surface protection structure. RL1 is the surface reflectance of the LED element 2, and R1 is the surface reflectance of the transparent substrate 31. RL2 is the synthetic reflectance between the transparent substrate 31 and the transparent adhesive 34 and the LED element 2, and RF is the synthetic reflectance between the transparent substrate 31 and the transparent adhesive 34 and the black fiber mesh 35. X is the light emitting area ratio of the LED element 2 to the display panel 12. T is the synthetic light transmittance of the transparent pressure-sensitive adhesive 34 and the transparent substrate 31.

For example, the brightness W of the video light of the default white signal is 1,000 (cd / m ² ), the brightness B of the video light of the default black signal is 0.1 (cd / m ² ), and the light is incident on the display panel 12. The brightness A of the external light is 30 (cd / m ² ), the surface reflectance RL1 of the LED element 2 is 10%, and the combined reflectance RL2 between the transparent substrate 31 and the transparent adhesive 34 and the LED element 2 is 10%. The synthetic reflectance RF between the transparent substrate 31 and the transparent adhesive 34 and the black fiber mesh 35 is 5%. When the LED element 2 having a size of 1.0 mm in length and width is mounted with a pixel pitch of 1.5 mm, the light emitting area ratio X of the LED element 2 to the display panel 12 is about 40%. The synthetic light transmittance T of the transparent pressure-sensitive adhesive 34 and the transparent substrate 31 is about 70%. Therefore, according to the equations (2) to (4), the effect CI for improving the external light contrast is about doubled, and the external light contrast is significantly improved.

It is possible to freely combine each embodiment, and to appropriately modify or omit each embodiment. The above description is exemplary in all embodiments. It is understood that innumerable variations not illustrated can be assumed.

1,31 transparent board, 2 LED element, 2r red LED element, 2g green LED element, 2b blue LED element, 3 board, 4,34 transparent adhesive, 5,35 black fiber mesh, 6 sealing resin, 7 jigs , 8 LED board, 9 voids, 11, 12 display panel, 20 insulation coating layer, 21 UV light shielding coating layer, 22 light peeling coating layer, 23 pressing roller, 24 suction port, 25 ground wire, 101, 102 display device.

Claims

With the board
A plurality of light emitting elements arranged on the upper surface of the substrate so as to be separated from each other and having a light emitting surface on the opposite side of the substrate.
A black matrix layer made of fiber fitted between the plurality of light emitting elements, and
A pressure-sensitive adhesive that is in contact with the upper surface of the black matrix layer, is formed on the light emitting surface side of the plurality of light emitting elements, and has translucency.
Display panel.
Further comprising a translucent protective substrate formed on the transparent pressure-sensitive adhesive.
The display panel according to claim 1.
The black matrix layer is arranged with a gap between the black matrix layer and the upper surface of the substrate.
The display panel according to claim 1 or 2.
Further, a light peeling coating layer provided on the side surface of each light emitting element of the plurality of light emitting elements and the light emitting surface is provided.
The black matrix layer is in contact with the side surface of the plurality of light emitting elements via the light release coating layer.
The display panel according to any one of claims 1 to 3.
The black matrix layer is made of carbon fiber.
The display panel according to any one of claims 1 to 4.
The black matrix layer is made of resin fiber.
The display panel according to any one of claims 1 to 4.
The black matrix layer is made of a resin fiber kneaded with carbon black.
The display panel according to claim 6.
The pressure-sensitive adhesive is made of a resin of the same type as the black matrix layer.
The display panel according to claim 6 or 7.
Further comprising a translucent protective substrate formed on the transparent pressure-sensitive adhesive.
The black matrix layer is made of resin fiber and is made of resin fiber.
The pressure-sensitive adhesive and the protective base material are made of a resin of the same type as the black matrix layer.
The display panel according to claim 1.
The black matrix layer has a structure in which a plurality of warp threads and a plurality of weft threads are woven in a single layer.
Each warp and weft consists of two fibers arranged side by side.
The display panel according to any one of claims 1 to 9.
The plurality of display panels according to any one of claims 1 to 10 are provided.
The plurality of display panels are arranged to form one screen.
Display device.
(A) Prepare a substrate on which a plurality of light emitting elements are mounted on the same surface so as to be separated from each other.
(B) A fiber black matrix layer is fitted in the gap between the light emitting elements.
(C) A light-transmitting pressure-sensitive adhesive is applied onto the black matrix layer and the light-emitting element.
(D) The pressure-sensitive adhesive is covered with a translucent protective base material.
(E) By pulling up the black matrix layer and pressing it against the pressure-sensitive adhesive, a gap is formed between the black matrix layer and the substrate.
(F) After the step (e), the adhesive is cured.
How to manufacture the display panel.
(G) The protective substrate is removed after the step (f).
The method for manufacturing a display panel according to claim 12.